NASHVILLE -- Jake Locker's left shoulder has been popped back into place twice this season, and now it's just a matter of time before the inevitable happens -- another traumatic episode and, eventually, surgery.

That's the opinion of a renowned Nashville doctor who specializes in the treatment of shoulder dislocations like those the Titans quarterback suffered over the first four games.

The first occurred in the season opener against the Patriots on Sept. 9, when Locker made a tackle. The second happened against the Texans on Sunday when he was sacked.

An MRI revealed no structural damage, coach Mike Munchak said Monday. Locker didn't miss a start after the previous popping out of his non-throwing shoulder, but the coach was taking a cautious approach about this week's road game against the Vikings.

"It surprised a lot of us how quickly and how good he felt within 48 hours or 72 hours of that injury last time," Munchak said. "I hope he is that way so we can make the decision on what's best for him and the team at that point. … If we don't feel he can function or play, obviously he won't play."

Dr. Mike Pagnani, director of Nashville Knee and Shoulder Center, is considered an authority on treating shoulder dislocations in football players. He was a team physician for the New York Giants and is a consultant for the Miami Dolphins. He also was head physician for the Nashville Predators from 1998-2007.

He has not been involved in Locker's treatment and has no direct knowledge of the specifics of his injury, but Pagnani said he believes the Titans should rest the second-year pro a few weeks so the shoulder will have time to strengthen.

A dislocation occurs when ligaments are torn off the socket, which creates a space for the ball to slip out.

"Eventually the pain will go away," Pagnani said. "The risk is it's going to happen again, and it's probably just a matter of time before it does. He is going to go out there, and he is going get hit wrong and it's going to pop out again. And he'll go through this same scenario where they pop it back in, and he's going to be real sore for a week or two until he ultimately gets it fixed. …

"He's already had one trial of non-operative treatment and maybe I would give him one more shot at this. But if it popped out again that would probably be it. I would probably just fix it, and that would be the end of the season for him. … It just depends on the discretion of the player and the doctor to a degree as to how many episodes you are willing to put up with."

Munchak acknowledged that rest would serve Locker well. He said it's too early to know if the Titans, who play two games in the next 10 days, will turn to backup Matt Hasselbeck this week.

"It is just a matter of trying not to predict anything and just wait and see how he is," Munchak said of Locker. "We'll take it day by day."

Pagnani said recovery time from surgery -- which would re-attach ligaments to the socket and tighten the area around it -- would be 4-6 months.

Without surgery, he said, Locker's harness will have to be tightened and the Titans will have to keep their fingers crossed.